Planes and ships converged on the southern Indian Ocean Wednesday, resuming the hunt for wreckage from Flight MH370 after weather conditions improved, as grieving passengers' families demand answers about the ill-fated jet.

Gale force winds, driving rain and mountainous seas prevented any sorties being flown from Perth in Australia's west on Tuesday, but 12 aircraft were deployed Wednesday, with South Korean planes joining the hunt for the first time.

"Today's search is split into three areas within the same proximity, covering a cumulative 80,000 square kilometres (30,000 square miles)," said the Australian Maritime Safety Authority which is coordinating the operation.

Australian naval vessel the HMAS Success, which was forced to leave the storm-tossed region, has returned and was conducting a surface sweep of a zone where two objects were spotted this week.

AMSA said four Chinese ships had also reached the search area, in the quest to find physical proof that the Malaysia Airlines jet went down in the remote seas, and clues as to why it veered off course and vanished on March 8 with 239 passengers and crew on board.

Australian Prime Minister Tony Abbott said the search -- now in a recovery phase -- would continue until there was no hope of finding anything.

"It is not absolutely open-ended but it is not something we will lightly abandon," he said ahead of a moment of silence in parliament in Canberra for victims of the doomed flight which included six Australians.

"The crash zone is about as close to nowhere as it's possible to be, but it's closer to Australia than anywhere else," he added in underscoring the remoteness of the search area as authorities seek to retrieve sunken or floating debris and the "black box" flight recorder.

- Undersea volcanoes -

In another complication, experts warned that a chain of undersea volcanoes runs directly through the search area, meaning the ocean floor is extremely rugged and constantly being reshaped by magma flows.

"It's very unfortunate if that debris has landed on the active crest area, it will make life more challenging," Robin Beaman, an underwater geology expert at Queensland's James Cook University told AFP.

"It's rugged, it's covered in faults, fine-scale gullies and ridges, there isn't a lot of sediment blanketing that part of the world because it's fresh (in geological terms)."

Abbott said "a considerable amount" of suspected debris had been sighted since the search began, although none has yet been retrieved.

"We are confident that some will be," he added.

The US Navy has sent a specialised device to help find the "black box" flight data recorder and cockpit voice recorder, along with a robotic underwater vehicle that can scan the ocean's depths.

Malaysia Airlines confirmed to AFP that the battery which powers the plane's black box will emit a locator signal of 30 days, once activated by contact with water, giving searchers less than two weeks to find a crash site.

Those efforts will be crucial in determining what caused the Boeing 777 to deviate inexplicably off its intended course between Kuala Lumpur and Beijing, and fly thousands of kilometres in the wrong direction.

Malaysia believes the plane was deliberately diverted by someone on board. In the absence of firm evidence, leading scenarios include a hijacking, pilot sabotage or a crisis that incapacitated the crew and left the plane to fly on auto-pilot until it ran out of fuel.

- 'Words can't ease pain' -

Two thirds of the passengers were Chinese, and relatives there have accused Malaysia of being deceitful and callous in their handling of the tragedy.

Scores of emotional relatives mounted a protest on Malaysia's embassy in Beijing on Tuesday, scuffling with guards and abusing the ambassador as they demanded to know what happened to their loved ones.

"Return our relatives," the family members shouted as they massed at the embassy gates. Another slogan went: "The Malaysian government are murderers."

Malaysia's ambassador to China Iskandar Sarudin later arrived at the hotel where relatives are staying, to face an angry tirade. Some shouted at him to kneel before them, while others launched a volley of abuse, calling him a "liar" and "rogue".

Malaysian authorities have defended their decision to release satellite analysis that determined the plane had plunged into the southern seas far off western Australia, possibly running out of fuel.

On Tuesday, they made public more details of the data used to conclude that the plane was lost.

It said the last complete contact between a satellite that was "pinging" signals to the flight came at 8:11 am Malaysian time (0011 GMT), with another "partial" signal eight minutes later.

The findings, by British satellite communications firm Inmarsat, suggest the plane was in touch nearly two hours after its scheduled 6:30 am landing time in Beijing, and right around the time it would have run out of fuel.

The analysis suggested the plane disappeared for good in the middle of the southern Indian Ocean but Malaysian officials said a precise location could not be determined.

burs-mp/mfc/pdh